This is a continuation application for an additional 5 years of support for a prospective and comparative study of mothers of adolescents and adults with autism spectrum disorders (ASD). We propose to investigate 4 specific aims: (1) to examine the factors that are associated with resiliency and vulnerability in midlife and aging mothers of adolescents and adults with ASD;(2) to examine daily stress measured objectively (with salivary cortisol) and subjectively (with self-report diaries) among mothers and adolescents and adults with ASD, (3) to examine change, and the predictors of change, in the manifestation of autism during adolescence and adulthood, and (4) to examine the antecedents and consequences of age-related major life transitions as experienced by adolescents and adults with ASD. Apart from the results of our ongoing study, little is known about the impact of caring for a child with ASD when he or she reaches adolescence and adulthood. Given the increasing prevalence of the diagnosis of ASD, there is a need to understand the full life course of this disorder. Our study constitutes the largest research sample (n=406, 78.3 percent of whom are still participating) of adolescents and adults with ASD and their midlife and aging families. Given the centrality of the family in the life of a person with ASD, and the reliance of the service system on the family as the primary source of support, there is an urgent public health and scientific need to understand the range of factors that influence the adaptation of adolescents and adults with ASD and the well-being of their families. This application seeks support to add a Phase II to our study, which will extend the longitudinal period to 12 years in the lives of families whose child with ASD was age 10-52 at the beginning Phase I and who will be age 22-64 when Phase II ends. Their mothers began the study when they were ages 32-82, and would be ages 44-94 at the study's end. The multiple points of measurement in Phases I and II will make it possible to examine time-varying predictors of short-term as well as longer-term change in the lives of caregiving mothers. Thus, this study is uniquely positioned to elucidate factors affecting the well-being of both mothers and their son or daughter with ASD across broad stretches of the life course.